Optical recording technology that enables consumers and others to record laser-written labels on specially coated recordable CD and DVD media has enjoyed notable commercial success. In light-activated thermal label-recording technology, a surface of the medium is coated with a writable layer of a material that changes appearance when it absorbs laser light of a predetermined wavelength. The color change interaction in a thermochromic imageable coating is enabled by phase transitions of the coating materials occurring at elevated temperatures. These phase transitions do not occur (and, so color does not develop) until the coating temperature reaches a certain value specific to the coating material. If the coating is irradiated with laser energy density that is not high enough to reach the phase transition, the color is not developed. Thus, if a writable layer is exposed to laser radiation with an irradiance distribution in which significant portions have insufficient irradiance to reach the color-forming (phase transition) temperature, some of the energy of the laser radiation is wasted. When relatively high-power laser radiation is required, cost increases can occur due to disproportionately higher laser cost. When multiple laser wavelengths are required, such as for color recording, differences in focal distance for the various laser wavelengths may require optics compatible with a focusing servo system. Thus, there is a need for further improvement in marking of media.